Which of the Following Mathematical Equations Corresponds to the Acid $K_{\mathrm{a}}=\frac{\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]}{[\mathrm{HB}]}$

Multiple Choice

Which of the following mathematical equations corresponds to the acid dissociation constant (K_a) ?

A) $K_{\mathrm{a}}=\frac{\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]}{[\mathrm{HB}]}$
B) $K_{\mathrm{a}}=\frac{\left[\mathrm{H}^{+}\right][\mathrm{HB}]}{\left[\mathrm{B}^{-}\right]}$
C) $K_{\mathrm{a}}=\frac{[\mathrm{HB}]\left[\mathrm{B}^{-}\right]}{\left[\mathrm{H}^{+}\right]}$
D) $K_{\mathrm{a}}=\frac{\left[\mathrm{B}^{-}\right][\mathrm{HB}]}{\left[\mathrm{H}^{+}\right]}$
E) $K_{\mathrm{a}}=\frac{\left[\mathrm{H}^{+}\right]\left[\mathrm{B}^{-}\right]}{[\mathrm{HB}]}$